Prep the pan: Line the bottom of a 9-inch springform pan with parchment and lightly grease the sides.
Preheat the oven to 325°F (163°C).
Make the crust: In a bowl, combine crushed Biscoff cookies, melted butter, brown sugar, and salt. Mix until the crumbs look like wet sand.
Form the base: Press the mixture firmly into the bottom and about 1 inch up the sides of the pan. Use a flat-bottomed glass for an even layer.
Par-bake: Bake the crust for 8–10 minutes until fragrant.
Let it cool while you make the filling. Keep the oven at 325°F (163°C).
Beat the cream cheese and sugar: In a large bowl, beat the cream cheese and granulated sugar on medium speed until smooth and fluffy, about 2 minutes. Scrape the bowl well.
Add pumpkin and sour cream: Mix in the pumpkin puree, sour cream, and vanilla until fully combined and silky.
Spice and thicken: Add cinnamon, ginger, nutmeg, cloves (if using), salt, and cornstarch.
Mix on low until just incorporated.
Add eggs: Beat in the eggs one at a time on low speed, just until combined. Do not overmix. Tap the bowl to release air bubbles.
Fill the pan: Pour the batter over the crust.
Smooth the top with an offset spatula and tap the pan gently on the counter.
Bake: Place the pan on the middle rack and bake for 55–70 minutes. The center should jiggle slightly like set Jell-O; the edges should look set.
Cool gradually: Turn off the oven, crack the door, and let the cheesecake rest inside for 45 minutes. Then move it to a wire rack to cool completely.
Chill: Cover and refrigerate for at least 6 hours, preferably overnight, to fully set and develop flavor.
Make the topping: Gently warm the Biscoff spread in a microwave or small pot until pourable.
Stir in 2–3 tbsp heavy cream to reach a smooth, spreadable consistency.
Finish and garnish: Release the chilled cheesecake from the springform pan. Spread the Biscoff topping over the surface. Sprinkle with crushed Biscoff cookies and add whipped cream if you like.
Slice and serve: Use a hot, dry knife for clean slices, wiping between cuts.
Enjoy cold or slightly cool.